core

#### Note A

In this image:

- The GREEN marks should work because the line/curve (or edge if it is a surface) that is closest to the marks is a line/curve that is in the plane that defines the slot.

- The RED mark will not work because the line (or edge if it is a surface) that is closest to the mark is a line/curve that is not in the plane that defines the slot.

- The YELLOW mark will work if the surface is a cylinder.